July 31, 2013

Spitzer Spots Hula Hoop Stars

Astronomers have discovered a young stellar system known as YLW 16A containing three developing stars that work together like a hula hoop.

Two of the stars within YLW 16A are surrounded by a disk of material left over from the star-formation process, and as the two stars whirl around each other, they periodically peek from the disk that girds them like a hula hoop. The hoop appears to be misaligned from the central star pair, most likely due to the disrupting gravitational presence of the third star orbiting the system.

The system cycles through bright and faint phases, with the central stars playing a game of cosmic peek-a-boo as the disk twirls around them. Scientists believe that this disk will go on to spawn planets and other celestial bodies that make up a solar system.

Astronomers using NASA's Spitzer Space Telescope observed YLW 16A in infrared light emitted by gas and dust in the disk. NASA said this stellar system is the fourth example of a star system known to "blink" in such a manner.

According to the space agency, the finding suggests that these systems might be more common than previously believed.

Star systems like YLW 16A offer scientists a way to study how planets form in these environments. The planets can orbit one or both of the stars in the binary star system. These worlds are referred to as circumbinary planets.

"These blinking systems offer natural probes of the binary and circumbinary planet formation process," said Peter Plavchan, a scientist at the NASA Exoplanet Science Institute and Infrared Processing and Analysis Center at the California Institute of Technology, Pasadena, California and lead author of a new paper accepted for publication in Astronomy & Astrophysics.

NASA's Spitzer telescope is known for being able to pick out stars, but it has recently shown off its skills in checking out carbon dioxide emissions from Comet ISON. This comet has been making its way closer and closer to the sun and is on track to give backyard astronomers a specular show this fall. Recently, Spitzer observations indicated that Comet ISON is slowly and steadily spewing out gas emission in a tail about 186,400 miles long.

"Previous observations made by NASA's Hubble Space Telescope and the Swift Gamma-Ray Burst Mission and Deep Impact spacecraft gave us only upper limits for any gas emission from ISON. Thanks to Spitzer, we now know for sure the comet's distant activity has been powered by gas," said Carey Lisse, leader of NASA's Comet ISON Observation Campaign and a senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.